Turbulent jet computations based on MRT and Cascaded Lattice Boltzmann models

TL;DR

This paper compares two Lattice Boltzmann models for simulating turbulent jet flow, demonstrating that the newer FCLB model without explicit turbulence modeling can outperform traditional methods in high-resolution, nonuniform grid simulations.

Contribution

The study introduces the FCLB model for turbulent flow simulation on nonuniform grids, showing its advantages over the traditional MRT model with LES.

Findings

FCLB model performs better in certain aspects than the MRT model.

Both models are feasible for turbulent jet flow simulation.

High-resolution simulations with over a billion DOF are achieved.

Abstract

In this contribution a numerical study of a turbulent jet flow is presented. The simulation results of two different variants of the Lattice Boltzmann method (LBM) are compared. The first is the well-established D3Q19 MRT model extended by a Smagorinsky Large Eddy Simulation (LES) model. The second is the D3Q27 Factorized Cascaded Lattice Boltzmann (FCLB) model without any additional explicit turbulence model. For this model no studies of turbulent flow with high resolution on nonuniform grids existed so far. The underlying computational procedure uses a time nested refinement technique and a grid with more than a billion DOF. The simulations were conducted with the parallel multi physics solver VIRTUALFLUIDS. It is shown that both models are feasible for the present flow case, but the FCLB outperforms the traditional approach in some aspects.